Magneto



May 27, 1941. w. D. CROCKER IAGNETO Filed lay 15, 1940 2 Sheets-Sheet 1 ATTORNEY.

May 27, 1941.

W. D. CROCKER MAGNETO Filed May 15, 1940 2 Sheets-Sheet 2 I IIIIIL ATTORNEY.

Patented May 27, 1941 2,243,416 MAcNE'ro William D. Crocker, Sp

to American Bosch 13 Claims.

The present invention relates to magnetos for electrical ignition of internal combustion engines.

The primary object of the invention is to promagnets and coils and with a laminated sheet metal rotor for producing four ignition impulses per rotation, wherein the distributor rotor is mounted on the magneto rotor shaft and an impulse coupling is provided. In these drawings,

Fig.1 is a longitudinal elevation, mostly in central section, of a flange mounting magneto; Fig. 2 is an elevation thereof, mostly in central transverse section; Flg. 3 is an end elevation, partly in section, of the bearing and interrupter bracket of the magneto; Fig. 4 is an elevational side view of the bracket; Fig. 5 is a rear elevation of the bracket showing the interrupter assembly mounted thereon; Fig. 6 is an end elevation of the distributor or rear end of the magneto; Fig. '7 is a sectional detail showing the attachment of stator laminations to the magneto frame; Fig. 8 is a fragmentary detail of the spring connection extending from the ignition coil terminal; and Fig. 9 is a central longitudinal section of a fragment of a similar magneto adapted for a timer mounting or timer shaft drive.

Referring to the embodiment of Figs. 1-7, the

reference numeral l designates a unitary die-cast 3 frame open at its opposite front and rear ends and having near its front or drive end an integral cross member 2 which provides a support for the ball bearing 3 and the oil seal 4. A longitudinal cylindrical extension 5 of the frame forms with the cross member a pocket 6 for an impulse or a drive coupling 1 of any suitable type and also provides a flange I having openings at 9 for mounting the magneto on an engine casing for driving connection with the cam shaft or crank shaft thereof in proper speed ratio and timing The rear end of the frame I is open for its full height and width for accommodation of a distrib utor plate M which is fastened to thickened interior portions of the frame by screws II. The bottom of the frame is open at l2 which, with the square box l3 perforated at H and i5 and held by screws It, forms a labyrinth ventilator. As a result of this construction, the flow of air through the ventilator during the operation of ringfleld, Mass, assignor Corporation, Springfield, Mass., a corporation of New York Application May 15, 1940, Serial No. 335,243

the magneto, as indicated by the arrows in Fig. 1, is at such a low rate that any dust particles or water drops suspended in the entering air will be precipitated in the tortuous passage without passing into the magneto, and at the same time the gases formed at the contacts of the interrupter and at the spark gaps of the distributor will be suiliciently diluted by circulation of the air within the magneto to prevent any abnormal corrosive action thereby. Furthermore, upon change of temperature within the magneto, or a difference thereof with respect to the outside atmosphere, a restrictive breathing action is permitted by the ventilator. On a circular seat on the base in the interior of the magneto is fastened by screws H a bracket l8 providing a rigid support for the rear bearing 19 for the magneto rotor shaft 20 and supporting on its rear face the interrupter assembly including a pivoted lever 2i cooperative with the cam 22 on the rotor shaft for periodic interruption of the primary ignition circuit of the magneto in the well known way. This bracket also has in one of its side walls a lubricating reservoir containing an oil-soaked felt plug 23 pressedagainst an oil-soaked wiok 24 extending around the porous composition plain bearing 19. The cover or separate sealing member 26 is held tightly in place by staking it against the gasket 21, around a shoulder of the reservoir, thus sealing the reservoir to the outside against the loss of oil and the entrance of foreign matter when the magneto is supported upright or upside down or in any other position on the engine.

The riveted stack of magnetic lamination's comprising pole pieces 28 and upright arms 29, and the riveted stacks comprising pole pieces 30,

are welded at 3i and 32 to the magnets 33 and form two unit assemblies, and are rigidly held in position in the frame by screws 34 against upper and lower thickened frame abutments 35. The stator structure comprises the unit assemblies as aforesaid together with the ignition coil 36 having core 31 and primary and secondary windings. This core comprises a stack of magnetic laminations riveted at each end by. a stud 38 having a projecting portion or handle 39 of larger diameter for removing and replacing the coil. Underneath the washer 40 at the front end of the stack is rigidly held a bent fiat spring 4| arranged to press against lugs 42 inside the frame and maintain the core 31 in good resilient magnetic contact with the ends of the upstanding arms 29.

As a result of thisconstr'uct'ion, the die cast frame I may have comparatively thin .w-alls since it is strengthened by/the thickened ini 'rior pdrtions as aforesaid and thereby maintains substantially unchanged under severe vibration in service the air gap between'the rotor and stator. The frame is further strengthened near its drive end by the cross member 2, the contracted and flanged cylindrical extension 5, and the stator assemblies, and near its rear end by the bracket [8 and the distributor platelfl. The thickened portions also provide for screw connection of certain parts to the frame, and the full open rear end of the frame provides for assembly of the parts therein. The circular seat for the bracket l8 may be machined in one boring Operation with the cross member 2.

The magnetic rotor comprises a stack 43 of magnetic lamina'tions, of substantially bar form in end view, riveted at 44 and securely pressed on the knurled portion 45 of the shaft 20, the faces of the stack, and also of the stator pole pieces, being ground to diameter for the proper air gap therebetween. The stack 43 is held longitudinally on the shaft between the ball bearing 3 and the plain bearing I 9 with washers as shown between its end faces and those bearings. The drive end of shaft 20 extends intopocket 8 where it is fastened to the driven member of impulse coupling 1. The rear end of the shaft has a portion forming the cam 22, and a terminal portion 46 with a peripheral flat on which the distributor rotor 47 is held ,in predetermined angular position by the bent flat spring 48.- I

The distributor plate H! of insulating material is fastened to the frame as aforesaid with the- A usual gasket therebetween. The lower rearward- 1y extending portion of this plate has fouroutlets 49 with sockets arranged in angularly offset and stepped relation for push'terminals on the sparkplug cables 50 as indicated particularly in Fig. 6. These outlets are connected by usual metal inserts to electrodes in equally spaced circular arrangements to form a spark gap relationship with the distributor rotor electrode 52. The dis tributor plate also has a low tension terminal for connection to a magneto grounding switch (not I shown) the spring 53 being arranged in rubbing contact with the live condenser connector 54.

The conductor 55, extending as an insert in the distributor plate, has its upper projection 56 encompassed by an extruded socket 51 in the bent flat spring 58 of bronze which extends into a depressed fiat of slot 59 on the inside surface of the plate In (see Figs. 1 and 8) to keep the spring from turning on the projecting end of insert 55 out of contact with the live terminal button 60 of the high tension winding of the ignition coil 36. The plate also, has two interior projections 6! (Figs. 1 and 6) in alinement with the respective handles 39 to prevent the coil core 31 from vibrating rearwardlyfrom engagement with the arms 29 when the magneto is in operation partic--' ularly in downwardly inclined position. The conductor 55 has its other end portion 62, with collar 63 riveted thereon, projecting centrally of the axis of rotation of the distributor rotor electrode 52. The electrode 52 has a central opening surrounding this collar with a circular gap or clearance across which jump the high tension current impulses from the ignition coil when current is supplied to the sparkplug cables sequentially.

In the embodiment of Fig.- 9, the same frame 64 is used except that the fiang mounting memher is replaced by a circular fi ring 65, while the distributor plate and interior parts of the magneto are substantially identical. The timer shaft 65 with its tongue 61 is fastened to the driving member of the impulse coupling 68 and is journaled inhearings in the timer mounting 69 hav- 'ing an oiler 10. The magneto is usually operated in a vertical position or inclined thereto and is driven by the timer shaft of the engine.

The operation of these two embodiments of magnetos will now be understood. Furthermore it will be understood that, among other things, this construction of frame with its reinforcing and strengthening means, certain features of the distributor connection between the high tension terminal of the coil and the distributor rotor electrode, and the stator unit assemblies fastened in the frame, may be used in various other types of magnetos, as for instance oscillatory instead of rotary, or distributing gearing replacing the distributor rotor mounted directly on the magneto rotor, other thanfour sparks per rotation of the magneto, and with other types of magnetic circuit as for instance a permanent magnet rotor with a magnetically conducting stator. These and other modifications are intended to be covered within the broadest interpretation of the appended claims.

Some of the features common to these magnetos and those disclosed in my application Serial No. 335,244 filed concurrently herewith are claimed therein and not in this application, comprising generally the removable coil unit, the bearing lubricating arrangement and the magneto short-circuiting connection.

Having thus described my invention, what I opening at its rear end for substantially its full height and width and also having a circular opening at its opposite driving'end formed by contracting the frame into a cylindrical extension; a magnetic stator detachably fastened in said frame; a magnetic rotor cooperative with said stator; said frame having inits interior an in tegral cross member which forms a bearing support for the drive end of said rotor and which defines a coupling pocket in the cylindrical extension; in said pocket a coupling connected to the drive end of said rotor; a bracket detachably connected to said frame for supporting the rear end of said rotor; and a detachable distributor plate covering said opening at the rear end of the frame; said frame having thickened portions for stiffening it and for fastening to it the detachable elements comprising the stator structure,

distributor plate and bracket.

2. In a magneto; an integral frame having an opening at its rear endfor substantially its full height and width and also having a circular opening at its opposite driving end formed by contracting the frame into a cylindrical extension; a magnetic stator detachably fastened in said frame; a magnetic rotor cooperative with said stator; said frame having in its interior an integral cross member which forms a bearing support for the drive end of said rotor and which defines a coupling pocket in the cylindrical extension; in said pocket a coupling connected to the drive end of said rotor; a bracket detachably thickened interior portions for stiffening the frame and for fastening thereto the detachable elements comprising the stator structure, distributor plate and bracket.

3. In a magneto; an integral frame having an opening at its rear end for substantially its full height and width and also having a circular opening at its opposite driving end formed by contracting the frame into a cylindrical extension; a magnetic stator detachably fastened in said frame; a magnetic rotor cooperative with said stator; said frame having in its interior an integral cross member which forms a bearing support for the drive end of said rotor and which defines a coupling pocket in the cylindrical extension; in said pocket a couplingconnected to the drive end of said rotor; a bracket detachably connected to said frame for supporting the rear end 'of said rotor; and a detachable distributor plate covering said opening at the rear end of the frame; said frame having an outer fit ring on the exterior of said cylindrical extension for timer-mounting the magneto and also having thickened interior portions for stiffening the frame and for fastening thereto the detachable elements comprising the stator structure, distributor plate and bracket.

' 4. In a magneto; an integral frame open at its opposite ends and also open at its bottom; a stator structure arranged in said frame; a magnetic rotor cooperative with the stator structure; a distributor having a plate at one end of the frame; and a perforated ventilator for the distributor arranged over the opening in the bottom of the frame and forming with said opening a labyrinth air passage between the exterior and interior of the magneto.

5. In a magneto; a frame having an opening;

, a stator structure arranged in said frame; a

magnetic rotor cooperative with the stator structure; and a perforated ventilator arranged over said opening and forming with the frame a labyrinth air passage between the exterior and interior of the magneto.

6. In a magneto; an integral frame open at its opposite ends and also open at one of its faces between said opposite ends; a stator structure arranged in said frame; a magnetic rotor cooperative with the stator structure; a distributor having a plate at one end of the frame; and a per,- foratedyentilator for the distributor arranged over the opening'in the face and forming with the frame a labyrinth air passage between the ex terior and interior of the magneto.

'7. In a magneto; a frame having abutments; a rotor comprising magnetic conducting 'laminations; an ignition coil having a laminated core projecting at opposite ends thereof; and two stator assemblies each comprising a permanent magnet and two laminated. pole pieces welded thereto near the respective poles thereof; each of said pole pieces being detachably secured to said abutments, whereby all pole pieces are main-.

tained in cooperation with said rotor and one pole pieee'of each assembly is maintained in magnetic contact with-a respective end of the coil core.

8. In a magneto; a magnetic stator including an ignition coil having a high tension terminal; a magnetic rotor cooperative with said stator; a distributor rotor driven by said magnetic rotor; a distributor plate having sparkplug terminals cooperative with said distributor rotor; a spring conductor fastened to said plate and extending into resilient electrical contact with the coil terminal; and in said distributor plate an insert with projecting ends for electrically connecting said spring conductor to said distributor rotor.

9. In a magneto; a frame open at one end; in said frame a magnetic stator including upright arms, and also including an ignition coil having a core bridging said arms and spring meansresiliently holding said core in said bridging position; a magnetic rotor cooperative with said stator; and a plate fastened over the open end of said frame and having means constructed and arranged to prevent said core from working off said bridging position,

10. In a magneto; a magnetic stator including an ignition coil having a high tension terminal; a magnetic rotor cooperative with said stator; a distributor rotor driven by said magnetic rotor; a distributor plate having sparkplug terminals cooperative with said distributor rotor; a spring conductor extending into electrical contact with the coil terminal; and means electrically connecting said spring conductor to said distributor rotor; said distributor plate having a depression in which said conductor rests to hold it from turning out of contact with said coil terminal.

11. In a magneto; a magnetic stator including an ignition coil having a high tension terminal; a magnetic rotor cooperative with said stator; a distributor rotor driven by said magnetic rotor; a distributor plate having sparkplug terminals cooperative with said distributor rotor; a conductor projecting from said plate and extending to the center of rotation of said distributor rotor; and a flat conductor electrically connected to said projecting end of said conductor and extending into contact with the coil terminal; said distributor plate having a slot into which said flat conductor extends to prevent it from turning around said conductor out of contact with the coil terminal.

12. In a magneto; a magnetic stator including an ignition coil having a high tension terminal; a magnetic rotor cooperating with said stator; a distributor rotor driven by said magnetic rotor and having a distributor electrode; a distributor plate having sparkplug terminals cooperative with said electrode; a spark gap connection having one electrode extending through said distribiutor electrode along the axis of rotation thereof; and electrical connecting means connecting the coil terminal to said gap electrode.

13. In a magneto; a magnetic stator including an ignition coil having a high tension terminal; a magnetic rotor cooperating with said stator; a

distributor rotor driven by said magnetic rotor.

and having a distributor electrode; a distributor plate having sparkplug terminals cooperative with said electrode; a conductor insert in said distributor plate extending to the center of rotation of said distributor electrode; a gap connection electrode arranged over the end of said conductor and extending through an opening in said vdistributor electrode on the axis of rotation thereof; and electrical means for connecting the coil terminal to said insert,

WILLIAM D. CROCKER. 

